TABLE 2.
Thermodynamic parameters obtained from the simultaneous fitting of different sets of thermal unfolding profiles of SH3 at pH 3.0, using the three-state model described in the text
| Data set* | TI (°C) | TU (°C) | ΔHI (TI) (kJ × mol−1) | ΔHU (TU) (kJ × mol−1) | ΔCp (50°C) (kJ × K−1 × mol−1) |
|---|---|---|---|---|---|
| A | 56.6 ± 0.3 | 55.5 ± 0.2 | 119 ± 1 | 181 ± 2 | 2.2 ± 0.2 |
| B | 57.0 ± 0.2 | 53.6 ± 0.3 | 120 ± 1 | 166 ± 5 | 2.8 ± 0.1 |
| C | 56.6 ± 0.8 | 54.6 ± 0.2 | 104 ± 4 | 180 ± 2 | 2.4 ± 0.1 |
| D | 56.6 (f) | 55.6 ± 0.2 | 119 (f) | 178 ± 1 | 2.2 ± 0.1 |
| E | 56.6 (f) | 55.9 ± 0.1 | 119 (f) | 183 ± 1 | 2.2 ± 0.1 |
For the sake of simplicity, the parameters corresponding to the values of the different observables for the individual states have not been included. The uncertainty of each parameter corresponds to the standard error of the fit. Parameters marked with ‘f’ have been fixed to the corresponding values of data set A.
Data set A consisted of five Cp curves obtained at five different sample concentrations between 0.03 mM and 4.8 mM; data set B consisted of the Cp curve at 4.8 mM plus an unfolding profile obtained by NMR at 5.4 mM; data set C consisted of the Cp curve at 0.76 mM, a near-UV CD curve at 0.69 mM, and an NMR profile at 0.68 mM; data set D consisted of a Cp curve at 0.15 mM, a near-UV CD curve at 0.14 mM, and a far-UV CD curve at 0.14 mM; data set E consisted of a Cp curve at 0.03 mM and a far-UV CD curve at 0.028 mM.